The invention relates to an arrangement for operating a magnetically suspended, electromotoric drive apparatus and to a method for operating a magnetically suspended, electromotoric drive apparatus.
The contact-free suspension of rotating apparatuses such as electric motors with active, electrically controlled magnetic bearings is known. Apparatuses of this kind require elaborate safety apparatuses against power interruptions in order to prevent an uncontrollable and abrupt decay of the magnetic bearing force in the case of a power failure. An arrangement is known from EP 0 430 009 which safely brings a magnetically suspended or journalled rotor to a standstill in the event of a power interruption. This arrangement uses batteries as an auxiliary energy source which are activated when the power is interrupted in order to supply the electromagnetic bearings and the control electronics with electrical energy until the rotor reaches a safe standstill. An auxiliary energy source of this kind has the disadvantage that it is relatively expensive, in particular when the rotor is of relatively heavy design. A further disadvantage is to be seen in the fact that the auxiliary energy source requires a continuous maintenance.